Package org.apache.hadoop.hbase.zookeeper

Class ZKUtil

java.lang.Object
org.apache.hadoop.hbase.zookeeper.ZKUtil
@Private public final class ZKUtil extends Object
Internal HBase utility class for ZooKeeper.

Contains only static methods and constants.

Methods all throw KeeperException if there is an unexpected zookeeper exception, so callers of these methods must handle appropriately. If ZK is required for the operation, the server will need to be aborted.

  • Field Details

    • LOG

      private static final org.slf4j.Logger LOG

    • useMultiWarn

      private static boolean useMultiWarn

  • Constructor Details

  • Method Details

    • getParent

      public static String getParent(String node)
      Returns the full path of the immediate parent of the specified node.
      Parameters:
      node - path to get parent of
      Returns:
      parent of path, null if passed the root node or an invalid node

    • getNodeName

      public static String getNodeName(String path)
      Get the name of the current node from the specified fully-qualified path.
      Parameters:
      path - fully-qualified path
      Returns:
      name of the current node

    • watchAndCheckExists

      public static boolean watchAndCheckExists(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      Watch the specified znode for delete/create/change events. The watcher is set whether or not the node exists. If the node already exists, the method returns true. If the node does not exist, the method returns false.
      Parameters:
      zkw - zk reference
      znode - path of node to watch
      Returns:
      true if znode exists, false if does not exist or error
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • setWatchIfNodeExists

      public static boolean setWatchIfNodeExists(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      Watch the specified znode, but only if exists. Useful when watching for deletions. Uses .getData() (and handles NoNodeException) instead of .exists() to accomplish this, as .getData() will only set a watch if the znode exists.
      Parameters:
      zkw - zk reference
      znode - path of node to watch
      Returns:
      true if the watch is set, false if node does not exists
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • checkExists

      public static int checkExists(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      Check if the specified node exists. Sets no watches.
      Parameters:
      zkw - zk reference
      znode - path of node to watch
      Returns:
      version of the node if it exists, -1 if does not exist
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • listChildrenAndWatchForNewChildren

      public static List<String> listChildrenAndWatchForNewChildren(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      Lists the children znodes of the specified znode. Also sets a watch on the specified znode which will capture a NodeDeleted event on the specified znode as well as NodeChildrenChanged if any children of the specified znode are created or deleted. Returns null if the specified node does not exist. Otherwise returns a list of children of the specified node. If the node exists but it has no children, an empty list will be returned.
      Parameters:
      zkw - zk reference
      znode - path of node to list and watch children of
      Returns:
      list of children of the specified node, an empty list if the node exists but has no children, and null if the node does not exist
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • listChildrenAndWatchThem

      public static List<String> listChildrenAndWatchThem(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      List all the children of the specified znode, setting a watch for children changes and also setting a watch on every individual child in order to get the NodeCreated and NodeDeleted events.
      Parameters:
      zkw - zookeeper reference
      znode - node to get children of and watch
      Returns:
      list of znode names, null if the node doesn't exist
      Throws:
      org.apache.zookeeper.KeeperException - if a ZooKeeper operation fails

    • listChildrenNoWatch

      public static List<String> listChildrenNoWatch(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      Lists the children of the specified znode without setting any watches. Sets no watches at all, this method is best effort. Returns an empty list if the node has no children. Returns null if the parent node itself does not exist.
      Parameters:
      zkw - zookeeper reference
      znode - node to get children
      Returns:
      list of data of children of specified znode, empty if no children, null if parent does not exist
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • nodeHasChildren

      public static boolean nodeHasChildren(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      Checks if the specified znode has any children. Sets no watches. Returns true if the node exists and has children. Returns false if the node does not exist or if the node does not have any children. Used during master initialization to determine if the master is a failed-over-to master or the first master during initial cluster startup. If the directory for regionserver ephemeral nodes is empty then this is a cluster startup, if not then it is not cluster startup.
      Parameters:
      zkw - zk reference
      znode - path of node to check for children of
      Returns:
      true if node has children, false if not or node does not exist
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • getNumberOfChildren

      public static int getNumberOfChildren(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      Get the number of children of the specified node. If the node does not exist or has no children, returns 0. Sets no watches at all.
      Parameters:
      zkw - zk reference
      znode - path of node to count children of
      Returns:
      number of children of specified node, 0 if none or parent does not exist
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • getData

      public static byte[] getData(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException, InterruptedException
      Get znode data. Does not set a watcher.
      Returns:
      ZNode data, null if the node does not exist or if there is an error.
      Throws:
      org.apache.zookeeper.KeeperException
      InterruptedException

    • getDataAndWatch

      public static byte[] getDataAndWatch(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      Get the data at the specified znode and set a watch. Returns the data and sets a watch if the node exists. Returns null and no watch is set if the node does not exist or there is an exception.
      Parameters:
      zkw - zk reference
      znode - path of node
      Returns:
      data of the specified znode, or null
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • getDataAndWatch

      public static byte[] getDataAndWatch(ZKWatcher zkw, String znode, boolean throwOnInterrupt) throws org.apache.zookeeper.KeeperException
      Get the data at the specified znode and set a watch. Returns the data and sets a watch if the node exists. Returns null and no watch is set if the node does not exist or there is an exception.
      Parameters:
      zkw - zk reference
      znode - path of node
      throwOnInterrupt - if false then just interrupt the thread, do not throw exception
      Returns:
      data of the specified znode, or null
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • getDataAndWatch

      public static byte[] getDataAndWatch(ZKWatcher zkw, String znode, org.apache.zookeeper.data.Stat stat) throws org.apache.zookeeper.KeeperException
      Get the data at the specified znode and set a watch. Returns the data and sets a watch if the node exists. Returns null and no watch is set if the node does not exist or there is an exception.
      Parameters:
      zkw - zk reference
      znode - path of node
      stat - object to populate the version of the znode
      Returns:
      data of the specified znode, or null
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • getDataInternal

      private static byte[] getDataInternal(ZKWatcher zkw, String znode, org.apache.zookeeper.data.Stat stat, boolean watcherSet, boolean throwOnInterrupt) throws org.apache.zookeeper.KeeperException
      Throws:
      org.apache.zookeeper.KeeperException

    • getDataNoWatch

      public static byte[] getDataNoWatch(ZKWatcher zkw, String znode, org.apache.zookeeper.data.Stat stat) throws org.apache.zookeeper.KeeperException
      Get the data at the specified znode without setting a watch. Returns the data if the node exists. Returns null if the node does not exist. Sets the stats of the node in the passed Stat object. Pass a null stat if not interested.
      Parameters:
      zkw - zk reference
      znode - path of node
      stat - node status to get if node exists
      Returns:
      data of the specified znode, or null if node does not exist
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • getChildDataAndWatchForNewChildren

      @Deprecated public static List<ZKUtil.NodeAndData> getChildDataAndWatchForNewChildren(ZKWatcher zkw, String baseNode) throws org.apache.zookeeper.KeeperException
      Deprecated.
      Unused
      Returns the date of child znodes of the specified znode. Also sets a watch on the specified znode which will capture a NodeDeleted event on the specified znode as well as NodeChildrenChanged if any children of the specified znode are created or deleted. Returns null if the specified node does not exist. Otherwise returns a list of children of the specified node. If the node exists but it has no children, an empty list will be returned.
      Parameters:
      zkw - zk reference
      baseNode - path of node to list and watch children of
      Returns:
      list of data of children of the specified node, an empty list if the node exists but has no children, and null if the node does not exist
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • getChildDataAndWatchForNewChildren

      @Deprecated public static List<ZKUtil.NodeAndData> getChildDataAndWatchForNewChildren(ZKWatcher zkw, String baseNode, boolean throwOnInterrupt) throws org.apache.zookeeper.KeeperException
      Deprecated.
      Unused
      Returns the date of child znodes of the specified znode. Also sets a watch on the specified znode which will capture a NodeDeleted event on the specified znode as well as NodeChildrenChanged if any children of the specified znode are created or deleted. Returns null if the specified node does not exist. Otherwise returns a list of children of the specified node. If the node exists but it has no children, an empty list will be returned.
      Parameters:
      zkw - zk reference
      baseNode - path of node to list and watch children of
      throwOnInterrupt - if true then just interrupt the thread, do not throw exception
      Returns:
      list of data of children of the specified node, an empty list if the node exists but has no children, and null if the node does not exist
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • updateExistingNodeData

      @Deprecated public static void updateExistingNodeData(ZKWatcher zkw, String znode, byte[] data, int expectedVersion) throws org.apache.zookeeper.KeeperException
      Deprecated.
      Unused
      Update the data of an existing node with the expected version to have the specified data. Throws an exception if there is a version mismatch or some other problem. Sets no watches under any conditions.
      Parameters:
      zkw - zk reference
      znode - the path to the ZNode
      data - the data to store in ZooKeeper
      expectedVersion - the expected version
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
      org.apache.zookeeper.KeeperException.BadVersionException - if version mismatch

    • setData

      public static boolean setData(ZKWatcher zkw, String znode, byte[] data, int expectedVersion) throws org.apache.zookeeper.KeeperException, org.apache.zookeeper.KeeperException.NoNodeException
      Sets the data of the existing znode to be the specified data. Ensures that the current data has the specified expected version.

      If the node does not exist, a KeeperException.NoNodeException will be thrown.

      If their is a version mismatch, method returns null.

      No watches are set but setting data will trigger other watchers of this node.

      If there is another problem, a KeeperException will be thrown.

      Parameters:
      zkw - zk reference
      znode - path of node
      data - data to set for node
      expectedVersion - version expected when setting data
      Returns:
      true if data set, false if version mismatch
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
      org.apache.zookeeper.KeeperException.NoNodeException

    • createSetData

      public static void createSetData(ZKWatcher zkw, String znode, byte[] data) throws org.apache.zookeeper.KeeperException
      Set data into node creating node if it doesn't yet exist. Does not set watch.
      Parameters:
      zkw - zk reference
      znode - path of node
      data - data to set for node
      Throws:
      org.apache.zookeeper.KeeperException - if a ZooKeeper operation fails

    • setData

      public static void setData(ZKWatcher zkw, String znode, byte[] data) throws org.apache.zookeeper.KeeperException, org.apache.zookeeper.KeeperException.NoNodeException
      Sets the data of the existing znode to be the specified data. The node must exist but no checks are done on the existing data or version.

      If the node does not exist, a KeeperException.NoNodeException will be thrown.

      No watches are set but setting data will trigger other watchers of this node.

      If there is another problem, a KeeperException will be thrown.

      Parameters:
      zkw - zk reference
      znode - path of node
      data - data to set for node
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
      org.apache.zookeeper.KeeperException.NoNodeException

    • setData

      private static void setData(ZKWatcher zkw, ZKUtil.ZKUtilOp.SetData setData) throws org.apache.zookeeper.KeeperException, org.apache.zookeeper.KeeperException.NoNodeException
      Throws:
      org.apache.zookeeper.KeeperException
      org.apache.zookeeper.KeeperException.NoNodeException

    • createEphemeralNodeAndWatch

      public static boolean createEphemeralNodeAndWatch(ZKWatcher zkw, String znode, byte[] data) throws org.apache.zookeeper.KeeperException
      Set the specified znode to be an ephemeral node carrying the specified data. If the node is created successfully, a watcher is also set on the node. If the node is not created successfully because it already exists, this method will also set a watcher on the node. If there is another problem, a KeeperException will be thrown.
      Parameters:
      zkw - zk reference
      znode - path of node
      data - data of node
      Returns:
      true if node created, false if not, watch set in both cases
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • createNodeIfNotExistsAndWatch

      public static boolean createNodeIfNotExistsAndWatch(ZKWatcher zkw, String znode, byte[] data) throws org.apache.zookeeper.KeeperException
      Creates the specified znode to be a persistent node carrying the specified data. Returns true if the node was successfully created, false if the node already existed. If the node is created successfully, a watcher is also set on the node. If the node is not created successfully because it already exists, this method will also set a watcher on the node but return false. If there is another problem, a KeeperException will be thrown.
      Parameters:
      zkw - zk reference
      znode - path of node
      data - data of node
      Returns:
      true if node created, false if not, watch set in both cases
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • createNodeIfNotExistsNoWatch

      public static String createNodeIfNotExistsNoWatch(ZKWatcher zkw, String znode, byte[] data, org.apache.zookeeper.CreateMode createMode) throws org.apache.zookeeper.KeeperException
      Creates the specified znode with the specified data but does not watch it. Returns the znode of the newly created node If there is another problem, a KeeperException will be thrown.
      Parameters:
      zkw - zk reference
      znode - path of node
      data - data of node
      createMode - specifying whether the node to be created is ephemeral and/or sequential
      Returns:
      true name of the newly created znode or null
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • createAndWatch

      public static int createAndWatch(ZKWatcher zkw, String znode, byte[] data) throws org.apache.zookeeper.KeeperException, org.apache.zookeeper.KeeperException.NodeExistsException
      Creates the specified node with the specified data and watches it.

      Throws an exception if the node already exists.

      The node created is persistent and open access.

      Returns the version number of the created node if successful.

      Parameters:
      zkw - zk reference
      znode - path of node to create
      data - data of node to create
      Returns:
      version of node created
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
      org.apache.zookeeper.KeeperException.NodeExistsException - if node already exists

    • asyncCreate

      public static void asyncCreate(ZKWatcher zkw, String znode, byte[] data, org.apache.zookeeper.AsyncCallback.StringCallback cb, Object ctx)
      Async creates the specified node with the specified data.

      Throws an exception if the node already exists.

      The node created is persistent and open access.

      Parameters:
      zkw - zk reference
      znode - path of node to create
      data - data of node to create
      cb - the callback to use for the creation
      ctx - the context to use for the creation

    • createAndFailSilent

      public static void createAndFailSilent(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      Creates the specified node, iff the node does not exist. Does not set a watch and fails silently if the node already exists. The node created is persistent and open access.
      Parameters:
      zkw - zk reference
      znode - path of node
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • createAndFailSilent

      public static void createAndFailSilent(ZKWatcher zkw, String znode, byte[] data) throws org.apache.zookeeper.KeeperException
      Creates the specified node containing specified data, iff the node does not exist. Does not set a watch and fails silently if the node already exists. The node created is persistent and open access.
      Parameters:
      zkw - zk reference
      znode - path of node
      data - a byte array data to store in the znode
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • createAndFailSilent

      private static void createAndFailSilent(ZKWatcher zkw, ZKUtil.ZKUtilOp.CreateAndFailSilent cafs) throws org.apache.zookeeper.KeeperException
      Throws:
      org.apache.zookeeper.KeeperException

    • createWithParents

      public static void createWithParents(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      Creates the specified node and all parent nodes required for it to exist. No watches are set and no errors are thrown if the node already exists. The nodes created are persistent and open access.
      Parameters:
      zkw - zk reference
      znode - path of node
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • createWithParents

      public static void createWithParents(ZKWatcher zkw, String znode, byte[] data) throws org.apache.zookeeper.KeeperException
      Creates the specified node and all parent nodes required for it to exist. The creation of parent znodes is not atomic with the leafe znode creation but the data is written atomically when the leaf node is created. No watches are set and no errors are thrown if the node already exists. The nodes created are persistent and open access.
      Parameters:
      zkw - zk reference
      znode - path of node
      Throws:
      org.apache.zookeeper.KeeperException - if unexpected zookeeper exception

    • deleteNode

      public static void deleteNode(ZKWatcher zkw, String node) throws org.apache.zookeeper.KeeperException
      Delete the specified node. Sets no watches. Throws all exceptions.
      Throws:
      org.apache.zookeeper.KeeperException

    • deleteNode

      public static boolean deleteNode(ZKWatcher zkw, String node, int version) throws org.apache.zookeeper.KeeperException
      Delete the specified node with the specified version. Sets no watches. Throws all exceptions.
      Throws:
      org.apache.zookeeper.KeeperException

    • deleteNodeFailSilent

      public static void deleteNodeFailSilent(ZKWatcher zkw, String node) throws org.apache.zookeeper.KeeperException
      Deletes the specified node. Fails silent if the node does not exist.
      Parameters:
      zkw - reference to the ZKWatcher which also contains configuration and operation
      node - the node to delete
      Throws:
      org.apache.zookeeper.KeeperException - if a ZooKeeper operation fails

    • deleteNodeFailSilent

      private static void deleteNodeFailSilent(ZKWatcher zkw, ZKUtil.ZKUtilOp.DeleteNodeFailSilent dnfs) throws org.apache.zookeeper.KeeperException
      Throws:
      org.apache.zookeeper.KeeperException

    • deleteNodeRecursively

      public static void deleteNodeRecursively(ZKWatcher zkw, String node) throws org.apache.zookeeper.KeeperException
      Delete the specified node and all of it's children.

      If the node does not exist, just returns.

      Sets no watches. Throws all exceptions besides dealing with deletion of children.

      Throws:
      org.apache.zookeeper.KeeperException

    • deleteChildrenRecursively

      public static void deleteChildrenRecursively(ZKWatcher zkw, String node) throws org.apache.zookeeper.KeeperException
      Delete all the children of the specified node but not the node itself. Sets no watches. Throws all exceptions besides dealing with deletion of children.
      Throws:
      org.apache.zookeeper.KeeperException - if a ZooKeeper operation fails

    • deleteChildrenRecursivelyMultiOrSequential

      public static void deleteChildrenRecursivelyMultiOrSequential(ZKWatcher zkw, boolean runSequentialOnMultiFailure, String... pathRoots) throws org.apache.zookeeper.KeeperException
      Delete all the children of the specified node but not the node itself. This will first traverse the znode tree for listing the children and then delete these znodes using multi-update api or sequential based on the specified configurations.

      Sets no watches. Throws all exceptions besides dealing with deletion of children.

      If the following is true:

      • runSequentialOnMultiFailure is true
      on calling multi, we get a ZooKeeper exception that can be handled by a sequential call(*), we retry the operations one-by-one (sequentially). - zk reference - if true when we get a ZooKeeper exception that could retry the operations one-by-one (sequentially) - path of the parent node(s)
      Throws:
      org.apache.zookeeper.KeeperException.NotEmptyException - if node has children while deleting if unexpected ZooKeeper exception if an invalid path is specified
      org.apache.zookeeper.KeeperException

    • deleteNodeRecursivelyMultiOrSequential

      public static void deleteNodeRecursivelyMultiOrSequential(ZKWatcher zkw, boolean runSequentialOnMultiFailure, String... pathRoots) throws org.apache.zookeeper.KeeperException
      Delete the specified node and its children. This traverse the znode tree for listing the children and then delete these znodes including the parent using multi-update api or sequential based on the specified configurations.

      Sets no watches. Throws all exceptions besides dealing with deletion of children.

      If the following is true:

      • runSequentialOnMultiFailure is true
      on calling multi, we get a ZooKeeper exception that can be handled by a sequential call(*), we retry the operations one-by-one (sequentially). - zk reference - if true when we get a ZooKeeper exception that could retry the operations one-by-one (sequentially) - path of the parent node(s)
      Throws:
      org.apache.zookeeper.KeeperException.NotEmptyException - if node has children while deleting if unexpected ZooKeeper exception if an invalid path is specified
      org.apache.zookeeper.KeeperException

    • submitBatchedMultiOrSequential

      private static void submitBatchedMultiOrSequential(ZKWatcher zkw, boolean runSequentialOnMultiFailure, List<ZKUtil.ZKUtilOp> ops) throws org.apache.zookeeper.KeeperException
      Chunks the provided ops when their approximate size exceeds the the configured limit. Take caution that this can ONLY be used for operations where atomicity is not important, e.g. deletions. It must not be used when atomicity of the operations is critical.
      Parameters:
      zkw - reference to the ZKWatcher which contains configuration and constants
      runSequentialOnMultiFailure - if true when we get a ZooKeeper exception that could retry the operations one-by-one (sequentially)
      ops - list of ZKUtilOp ZKUtil.ZKUtilOp to partition while submitting batched multi or sequential
      Throws:
      org.apache.zookeeper.KeeperException - unexpected ZooKeeper Exception / Zookeeper unreachable

    • partitionOps

      static List<List<ZKUtil.ZKUtilOp>> partitionOps(List<ZKUtil.ZKUtilOp> ops, int maxPartitionSize)
      Partition the list of ops by size (using estimateSize(ZKUtilOp)).

    • estimateSize

      static int estimateSize(ZKUtil.ZKUtilOp op)

    • listChildrenBFSNoWatch

      private static List<String> listChildrenBFSNoWatch(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      BFS Traversal of all the children under path, with the entries in the list, in the same order as that of the traversal. Lists all the children without setting any watches. - zk reference - path of node
      Returns:
      list of children znodes under the path if unexpected ZooKeeper exception
      Throws:
      org.apache.zookeeper.KeeperException

    • listChildrenBFSAndWatchThem

      private static List<String> listChildrenBFSAndWatchThem(ZKWatcher zkw, String znode) throws org.apache.zookeeper.KeeperException
      BFS Traversal of all the children under path, with the entries in the list, in the same order as that of the traversal. Lists all the children and set watches on to them. - zk reference - path of node
      Returns:
      list of children znodes under the path if unexpected ZooKeeper exception
      Throws:
      org.apache.zookeeper.KeeperException

    • toZooKeeperOp

      private static org.apache.zookeeper.Op toZooKeeperOp(ZKWatcher zkw, ZKUtil.ZKUtilOp op) throws UnsupportedOperationException
      Convert from ZKUtilOp to ZKOp
      Throws:
      UnsupportedOperationException

    • multiOrSequential

      public static void multiOrSequential(ZKWatcher zkw, List<ZKUtil.ZKUtilOp> ops, boolean runSequentialOnMultiFailure) throws org.apache.zookeeper.KeeperException
      Use ZooKeeper's multi-update functionality. If all of the following are true: - runSequentialOnMultiFailure is true - on calling multi, we get a ZooKeeper exception that can be handled by a sequential call(*) Then: - we retry the operations one-by-one (sequentially) Note *: an example is receiving a NodeExistsException from a "create" call. Without multi, a user could call "createAndFailSilent" to ensure that a node exists if they don't care who actually created the node (i.e. the NodeExistsException from ZooKeeper is caught). This will cause all operations in the multi to fail, however, because the NodeExistsException that zk.create throws will fail the multi transaction. In this case, if the previous conditions hold, the commands are run sequentially, which should result in the correct final state, but means that the operations will not run atomically.
      Throws:
      org.apache.zookeeper.KeeperException - if a ZooKeeper operation fails

    • processSequentially

      private static void processSequentially(ZKWatcher zkw, List<ZKUtil.ZKUtilOp> ops) throws org.apache.zookeeper.KeeperException, org.apache.zookeeper.KeeperException.NoNodeException
      Throws:
      org.apache.zookeeper.KeeperException
      org.apache.zookeeper.KeeperException.NoNodeException

    • logRetrievedMsg

      private static void logRetrievedMsg(ZKWatcher zkw, String znode, byte[] data, boolean watcherSet)

    • getServerNameOrEmptyString

      private static String getServerNameOrEmptyString(byte[] data)

    • waitForBaseZNode

      public static void waitForBaseZNode(org.apache.hadoop.conf.Configuration conf) throws IOException
      Waits for HBase installation's base (parent) znode to become available.
      Throws:
      IOException - on ZK errors

    • convert

      public static org.apache.zookeeper.KeeperException convert(DeserializationException e)
      Convert a DeserializationException to a more palatable KeeperException. Used when can't let a DeserializationException out w/o changing public API.
      Parameters:
      e - Exception to convert
      Returns:
      Converted exception

    • logZKTree

      public static void logZKTree(ZKWatcher zkw, String root)
      Recursively print the current state of ZK (non-transactional)
      Parameters:
      root - name of the root directory in zk to print

    • logZKTree

      private static void logZKTree(ZKWatcher zkw, String root, String prefix) throws org.apache.zookeeper.KeeperException
      Helper method to print the current state of the ZK tree.
      Throws:
      org.apache.zookeeper.KeeperException - if an unexpected exception occurs
      See Also:

    • positionToByteArray

      public static byte[] positionToByteArray(long position)
      Parameters:
      position - the position to serialize
      Returns:
      Serialized protobuf of position with pb magic prefix prepended suitable for use as content of an wal position in a replication queue.

    • parseWALPositionFrom

      public static long parseWALPositionFrom(byte[] bytes) throws DeserializationException
      Parameters:
      bytes - - Content of a WAL position znode.
      Returns:
      long - The current WAL position.
      Throws:
      DeserializationException - if the WAL position cannot be parsed